The present invention relates generally to indicating devices for indicating the existence or occurrence of a predetermined parameter and, more particularly, to a liquid crystal indicating device for indicating the flow of current through a circuit by virtue of a change in temperature in a heat generating element in the circuit.
Indicating devices for indicating the flow of current are particularly useful in such electrical devices as battery chargers since, without such indicators, it is impossible to ascertain whether a particular battery is being charged or is defective. Otherwise, the only way to ascertain whether a cell has been charged is to test the cell or actually use it after it has remained in the charger for the appropriate length of time. Thus, if a cell were defective or installed incorrectly in the charger, one could not know until after waiting until the cell should have charged, thereby wasting that time.
In the prior art, it is known to use an electric lamp to indicate the flow of charging current in a battery charger, such as disclosed in U.S. Pat. Nos. 3,245,726, 3,421,142 and 3,746,961. Although such devices have provided adequate results for certain applications, the indicators must be powered by the charging source, thereby utilizing system current and requiring a larger transformer. In addition, the light bulbs are susceptible to burn-out and could be unreliable as indicators. They also would require replacement and do involve extra costs and weight in the actual fabrication of the charger.
Accordingly, it is an object of the present invention to provide a new and improved liquid crystal indicator, and method for making same. Another object of the invention is to provide a new and improved liquid crystal indicator, and method for making same, for indicating the flow of current through a predetermined circuit.
It is also an object of the invention to provide a new and improved liquid crystal indicator, and method for making same, for indicating the flow of current through a predetermined circuit, wherein the indicator is not energized directly by current in the circuit.
It is a further object of the present invention to provide a new and improved liquid crystal indicator, and method for making same, for indicating the flow of current through rechargeable cells in a battery charger.
It is a further object of the present invention to provide a new and improved liquid crystal indicator, and method for making same, which is relatively lightweight and relatively inexpensive to make.
It is an additional object of the invention to provide a new and improved liquid crystal indicator, and method for making same, for indicating the flow of current through rechargeable cells in a battery charger, which is adapted to include a desired message in addition to or as part of the indicator.
Objects and advantages of the invention are set forth in part above and in part below. In addition, these and other objects and advantages of the invention will become apparent herefrom or may be appreciated by practice with the invention, the same being realized and attained by means of the instrumentalities, combinations and methodologies pointed out in the appended claims. Accordingly, the invention resides in the novel parts, arrangements, combinations, steps, methods and improvements herein shown and described.